How to add/remove words in the firefox custom spell check dictionary

I added a word to my Mozilla Firefox spell check personal dictionary by mistake the other day, and could not figure out how to remove it. Firefox seriously lacks custom dictionary management.

To open your profile directory do the following or use the “Open Profile Folder Firefox Add-on“…

Simply go to Start -> Run, enter:


Locate the profile you’re using (usually default.something).

Then, inside the folder you will find a file named “persdict.dat”.

Open that, and there you have it, your custom list of words.

Edit it how you like save, and restart Firefox.

All done!


  1. ab0z said,

    October 19, 2007 @ 12:09 am

    What about mac users? how then?

  2. Rayvin said,

    December 13, 2007 @ 6:07 am

    THANK YOU!!!
    I added a word by mistake and you saved me!
    Very helpful!

  3. Robert said,

    August 24, 2008 @ 1:06 am

    I am having the same problem with
    microsoft Works; It’s like you make a mistake, and you are stuck with it for life.

    Just give me the name of the file.


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